Keywords: NTS - Railroad Trestles - after 2.jpg Nevada Test Site Frenchman Flat <br /> The U S Army's 412th Engineer Construction Battalion erected five structures which duplicated the center sections of open-deck single-track truss railroad bridges for the Encore and Grable shots <br /><br /> Photograph taken after the test 808 NF-250 Federal Government of the United States 36 799019 -115 936441 PD-USGov Upshot-Knothole Encore Upshot-Knothole Grable Plumbbob Priscilla Truss bridges in the United States |